Recent work on early learning shows remarkable abilities in infancy with important implications for infants learning about their visual world (Fisr & Aslin, 2002) and about language (Gomez, 2008; Saffran, Aslin, & Newport, 1996). Much of the theoretical development involving early learning is based on effects measured immediately after a learning experience, however, recent work in the sleep literature shows that memories can be transformed with sleep (Diekelmann & Born, 2010; Walker & Stickgold, 2006). In the only work investigating the effects of sleep on infant learning, Gomez and colleagues have shown that sleep within a short window after familiarization appears to be necessary for retention of learning, even at 15 months of age when many infants are napping just once a day (Gomez, Bootzin, & Nadel, 2006; Hupbach, Gomez, Bootzin, & Nadel, 2009). The proposed work investigates the role of sleep in much younger 6 month olds on a foundational form of learning during a period when sleep architecture is in flux between neonatal and infant sleep, probing the extent to which memory consolidation is affected by immediate vs. delayed sleep over 2, 4, and 24 hours. This will be the first study of its kind to directly test the effects of seep on memory consolidation. It will also be the first to document infant sleep architecture in an attempt to relate different sleep variables that have been associated with memory consolidation in adults to memory consolidation in infants. The results will inform us about the effects of sleep on early memory consolidation, a question that has not yet been addressed in the literature. In addressing the problem of how learning is affected by sleep-dependent memory processes, these studies will represent an important first step in scaling up learning research to a real-worl constraint, the fact that knowledge is consolidated over sleep and over time. PUBLIC HEALTH RELEVANCE: Poor sleep is surprisingly prevalent in young children with just one disorder, sleep-disordered breathing, affecting 1-3% of all children (Montgomery- Downs, 2006) and affecting certain developmental populations such as children with Down Syndrome. Given the relationship between poor sleep and poor cognitive outcomes, the proposed work, in establishing baselines for sleep-dependent consolidation in typically developing 6 month olds will be important for understanding memory development in populations that are compromised. This is all the more urgent given that children with poor sleep score lower on measures of receptive vocabulary and on nonverbal intelligence and the fact that such deficits persist even in children who recover normal sleep by 3 years of age (Touchette, Petit, & Seguin, 2007). To the extent that later successes in learning build on a strong foundation of prior successes, a clearer understanding of the importance of sleep for forming that foundation is an important public health mission.